A ver si asi te queda mas claro:

http://opel-scan.ru/files/Opel_Motronic2.5.pdf


OCTANE CODING

Because of the sophistication of the KCU and timing control an octane coding plug is not considered necessary for the 20XE & C20XE engines. Octane adjustment is automatically selected according to operating conditions. Motronic 2.5 is programmed with
two different timing maps. These are Low Octane Number Map (more retarded timing) and High Octane Number Map (more
advanced dwell angle). The KCU selects the appropriate map according to the following conditions. Once knocking combustion
of more than 50 have occurred, the KCU switches to the Low Octane Map. Once approximately 8.5 minutes of knock-free
operation have passed, the KCU switches to the High Octane Map.